Sigma Alpha Epsilon (ΣΑΕ, also SAE) is one of the largest North American Greek-letter social college fraternities. It was founded at the University of Alabama on March 9, 1856. Of all existing national social fraternities today, Sigma Alpha Epsilon is the only one founded in the Antebellum South. Its national headquarters, the Levere Memorial Temple, was established on the campus of Northwestern University in Evanston, Illinois, in 1929.

As of 2015, Sigma Alpha Epsilon has initiated more than 325,000 members since badge numbers were first issued and has approximately 15,000 active undergraduate members at 218 active chapters as of March 2015, and 20 colonies. The fraternity has chapters and colonies in 50 states and provinces as of 2014. The creed of Sigma Alpha Epsilon, The True Gentleman, must be emulated by all prospective members. New members receive a copy of The Phoenix, the manual of Sigma Alpha Epsilon, for educational development. As of March 2014, Sigma Alpha Epsilon has eliminated pledging both locally and nationally.